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Title: Modelling of blood flow near arterial walls
Author: Hazel, A. L.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 1999
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In this thesis, theoretical models of fluid flows close to arterial walls are studied. There are two main areas of study: (i) Flow near an oscillating stagnation point. The existence of a stagnation point which oscillates in position as well as in strength has been observed at certain sites prone to occlusive arterial disease. The two oscillations can interact non-linearly, altering the mean shear stress distribution on the wall. The problem is studied analytically and numerically in two and three dimensions, where in the three-dimensional case the basic stagnation-point flow is axisymmetric. In the physiologically relevant regime, it is found that the positional oscillations break the symmetry of the system, shifting the point of lowest mean wall shear stress away from the centre of these oscillations. The mass transport properties of such a flow are also studied by calculating particle trajectories and mass fluxes. (ii) Flow over an isolated obstacle on a plane wall. The vascular endothelium is a monolayer of cells lining the arterial walls. The endothelial cells convert mechanical forces into biological responses and a dysfunction of this natural process is one of the many proposed mechanisms for the initiation of atherosclerosis. The endothelium is a non-uniform surface with crests at the cellular nuclei and troughs at junctions between cells. A model for a single endothelial nucleus raised above the cellular monolayer is considered here. The time- and length-scales are such that the local fluid behaviour is dominated by viscous forces and the steady Stokes equations are applicable. These equations are solved numerically by a boundary element collocation method and the total force on a variety of nuclear shapes is calculated. Further away from the nucleus, but still on a cellular length-scale, weak inertia effects are introduced. Fourier transform methods are then used to obtain a closed form solution for the pressures and stresses on the wall, which are investigated by asymptotic methods.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available